[The protective properties of the endotoxin protein]. / Protektivnye svoistva belka éndotoksina.

The isolation and properties of endotoxin protein, or lipid A-associated protein (LAP), from Shigella sonnei were described earlier (Zh. mikrobiol. epidemiol. immunobiol., 1991, No. 4, pp. 11-17, and No. 7). In this report the data on its protective activity are presented. In experiments on mice one nanogram of LAP injected i. v. protected 50% of the animals against i. p. challenge with 40 LD50 of virulent S. sonnei. Guinea pigs injected s. c. with 10 micrograms of LAP were protected against local (keratoconjunctival) challenge with S. sonnei, the efficiency of immunization being 58%. LAP preparations containing no detectable amounts of O-antigen (less than 0.003%) were found to have a protective effect. Hyperimmune anti-LAP rabbit serum prevented local infection when incubated with S. sonnei challenge inoculum before injection into guinea pigs. Both active and passive protection induced by LAP was specific since no effect was observed in animals challenged with Shigella flexneri. In the homologous system the protective effect of anti-LAP serum was abolished by the addition of protein-free LPS. These results are compatible with the hypothesis that the protective activity of LAP depends on the presence of minute amounts of O-antigen whose immunogenic effect is greatly amplified by the protein component of the natural endotoxin complex.

[The action of ribosomal preparations on nonspecific resistance to bacterial infection and on early tolerance to endotoxic shock]. / Deistvie ribosomal'nykh preparatov na nespetsificheskuiu rezistentnost' k bakterial'noi infektsii i ranniuiu tolerantnost' k éndotoksicheskomu shoku.

Ribosomal preparations from Shigella flexneri and Shigella sonnei, introduced parenterally into mice, enhance their resistance to infection with the causative agents of typhoid fever and staphylococci. This effect is considerably less pronounced than that produced by the preparation of homologous lipopolysaccharide isolated by Boivin's method. After the administration of ribosomes nonspecific resistance to bacterial infective agents lasts for a short time. Ribosomal preparations do not enhance the resistance of mice to the lethal action of endotoxin.

[Therapeutic effectiveness of ristomycin in the visceral form of actinomycosis (experimental research)]. / Terapevticheskaia éffektivnost' ristomitsina pri vistseral'noi forme aktinomikoza (éksperimental'nye issledovaniia).

Therapeutic efficacy of ristomycin in visceral actinomycosis, a severe disease difficult for diagnosis requiring long-term complex therapy was studied on 24 rabbits. The animals were divided into 4 groups. A model of thoracal actinomycosis was developed. 7 rabbits were treated with ristomycin. The other 7 rabbits were treated with ristomycin in combination with actinolysate, a specific immune preparation. 5 rabbits were treated with actinolysate alone and the other 5 rabbits received no treatment. alone and especially in combination with actinolysate was an efficient therapeutic agent for treatment of severe visceral actinomycosis. This allowed to recommend ristomycin for clinical trials in treatment of the disease.